Building on recent work on psychophysiological deviance in two late-adolescent, psychometrically defined populations believed vulnerable to developing psychosis, the project will investigate cognitive abnormalities in these groups. The goals of the project are (1) to refine objective psychophysiological selection criteria for identifying vulnerable individuals; and (2) to evaluate a theory of the information processing abnormalities manifested by these individuals, preparatory to developing cognitively oriented preventive interventions targeted at these abnormalities. Cognitive tasks derived from normative information processing models will be completed by subjects chosen for vulnerability to psychosis, as well as by dysthymic and non-psychiatric controls. These tasks are selected especially to involve anticipatory processing of affective and non-affective stimuli. Extensive psychophysiological measurement during task performance will demonstrate contrasts between vulnerable and control subjects' handling of affective stimuli. Based on task-specific information processing models, these psychophysiological abnormalities will implicate specific cognitive differences in the vulnerable individuals. These studies will enhance the early diagnosis and primary prevention of psychotic disorders, by strengthening a relatively untapped and underdeveloped domain of assessment for identifying vulnerable individuals. Psychophysiological predictors are especially promising as an adjunct to traditional screening methods, since current psychophysiological functioning may more directly tap the biochemical abnormalities which are suspected in psychosis. Of particular interest are known psychophysiological differences between the two vulnerable populations under investigation. By determining the cognitive basis of and refining psychophysiological markers for these differences, individually tailored preventive interventions can be designed which address the specific difficulties and/or vulnerabilities of each population.